package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import jakarta.annotation.PostConstruct;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.Collections;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Autowired
    private ISeckillVoucherService seckillVoucherService;

    @Autowired
    private RedisIdWorker redisIdWorker;

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Autowired
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }

    private BlockingQueue<VoucherOrder> orderTasks  = new ArrayBlockingQueue<>(1024*1024);

    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable{
        @Override
        public void run() {
            while (true) {
                try {
                    //1、获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2、创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                }
            }
        }

        private void handleVoucherOrder(VoucherOrder voucherOrder) {
            //1、获取用户
            Long userId = voucherOrder.getId();

            //2、创建锁对象
            RLock lock = redissonClient.getLock("lock:order:" + userId);

            //3、获取锁
            boolean isLock = lock.tryLock();

            //4、判断锁是否获取成功
            if (!isLock) {
                //获取锁失败
               log.error("不允许重复下单");
               return;
            }

            //ctrl+alt+t
            try {
                proxy.creatVoucherOrder(voucherOrder);
            } finally {
                //释放锁
                lock.unlock();
            }
        }
    }

    private IVoucherOrderService proxy;

     @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
         Long userId = UserHolder.getUser().getId();

         //1、执行lua脚本
         Long result = stringRedisTemplate.execute(
                 UNLOCK_SCRIPT,
                 Collections.emptyList(),
                 voucherId.toString(), userId.toString()
         );

         //2、判断结果是否为0
         int r = result.intValue();
         if (result != 0) {
             // 2.1、不为0，代表没有购买资格
             return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
         }

         // 2.2、为0，有购买资格，把下单信息保存到阻塞队列
         // 保存阻塞队列
         VoucherOrder voucherOrder = new VoucherOrder();

         //2.3、订单id
         long orderId = redisIdWorker.nextId("order");
         voucherOrder.setId(orderId);

         //2.4、用户id
         voucherOrder.setUserId(userId);

         //2.5、代金券id
         voucherOrder.setVoucherId(voucherId);

         //2.6、创建阻塞队列
         orderTasks.add(voucherOrder);

         //3、获取代理对象
          proxy = (IVoucherOrderService) AopContext.currentProxy();

         // 4、返回订单id
         return Result.ok(0);
    }
   /* @Override
    public Result seckillVoucher(Long voucherId) {
        //1、查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2、判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            //尚未开始
            return Result.fail("秒杀尚未开始");
        }
        //3、判断秒杀是否结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            //秒杀已经结束
            return Result.fail("秒杀已经结束");
        }
        //4、判断库存是否充足
        if (voucher.getStock() < 1) {
            //库存不足
            return Result.fail("库存不足");
        }
        Long userId = UserHolder.getUser().getId();
        //创建锁对象
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        //判断锁是否获取成功
        if (!isLock) {
            //获取锁失败
            return Result.fail("不允许重复下单");
        }
        //ctrl+alt+t
        try {
            //获取代理对象
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.creatVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }
      *//*  synchronized (userId.toString().intern()) {
            //获取代理对象
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.creatVoucherOrder(voucherId);
        }*//*
    }*/
    @Transactional
    public void creatVoucherOrder(VoucherOrder voucherOrder) {
        //5、一人一单
        Long userId = voucherOrder.getUserId();

        //5.1、查询订单
        Long count = query()
                .eq("user_id", userId)
                .eq("voucher_id", voucherOrder.getVoucherId())
                .count();

        //5.2、判断是否存在
        if (count > 0) {
            //用户已经下单过无法再下单
           log.error("用户已经下单过");
           return;
        }

        //6、扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherOrder.getVoucherId())
                .gt("stock", 0)
                .update();

        if (!success) {
            //库存不足
            log.error("库存不足");
            return;
        }

        //7、创建订单
        save(voucherOrder);
    }
}
